Aldehydes are well known useful compounds and are particularly useful as chemical intermediates, for example, to make the corresponding acids. Aldehydes of low molecular weight are condensed in an aldol reaction to produce derivatives used in the plasticizer industry. These materials are also used as intermediates for the manufacture of solvents, resins and dyes.
Numerous preparations are known for aldehydes. For example, M. Hudlicky, "Oxidations in Organic Chemistry," ACS Monograph 186, 1990, pp. 114-126 teaches the dehydrogenation and oxidation of primary alcohols to aldehydes using a variety of catalysts, including but not limited to, oxides of copper, cobalt and chromium; copper, silver and mixtures thereof; cupric oxide; platinum; platinum dioxide; ceric ammonium nitrate; sodium bromate; lead tetraacetate; hexavalent chromium; sodium or potassium dichromate; pyridinium dichromate; chromic acid; Jones reagent; Collins reagent; pyridinium chlorochromate; chromyl chloride; di-tert-butyl chromate; manganese dioxide; tetrachloro-o-benzoquinone; tetrachloro-p-benzoquinone; 2,3-dichloro-5,6-dicyano-p-benzoquinone; dimethyl sulfide and chlorine; N-chlorosuccinimide (NCS); dimethylsulfoxide (DMSO); and the like.
B. S. Furniss, et al., ed., Vogel's Textbook of Practical Organic Chemistry, New York: Longman Scientific & Technical, 1987, pp. 414-424 describe the preparation of a number of aldehydes, including the oxidation of primary alcohols to aldehydes including (1) oxidation of primary alcohols to the corresponding aldehyde using sodium dichromate; (2) butyraldehyde from butan-1-ol over sodium dichromate dihydrate; and (3) producing hexanal from hexanol using a catalyst of copper-chromium oxide deposited on pumice.
A number of oxidizing agents are shown as useful in the preparation of aldehydes including DMSO; ceric ammonium nitrate; chromium trioxide in dry pyridine, t-butyl chromate or dipyridine Cr.sup.(VI) oxide; potassium hypochlorite; iodosobenzene; chromic anhydride in dilute acetic acid; selenium dioxide; lead tetraacetate; and 1-chlorobenzo-triazole according to C. A. Buehler, et al., Organic Synthesis, New York: Wiley-Interscience, 1970, pp. 542-555.
See also Kirk-Othmer Encyclopedia of Chemical Technology, Third Edition, Vol. 1, New York: Wiley-Interscience, 1978, pp. 790-798. It indicates on page 795 that "The lower aldehydes may be prepared by oxidation of the corresponding alcohol with manganese dioxide or a sulfuric acid solution of potassium dichromate."
Primary alcohols are quantitatively oxidized to aldehydes in a few minutes at 0.degree. C. in CH.sub.2 Cl.sub.2 -0.35M aqueous NaOCl in the presence of catalytic amounts of 4-methoxy-2,2,6,6-tetramethylpiperidine-1-oxyl according to P. L. Anelli, et al., "Fast and Selective Oxidation of Primary Alcohols to Aldehydes or to Carboxylic Acids and of Secondary Alcohols to Ketones Mediated by Oxoammonium Salts Under Two-Phase Conditions," J. Org. Chem., 1987, Vol. 52, pp. 2559-2562. It was noted that cocatalysis by Br.sup.- and buffering of pH at 8.6 with NaHCO.sub.3 are also required.
T. Takaya, et al. in "Novel Reactions of Iodosobenzene with Various Organic Compounds," Bull. Chem. Society of Japan, Vol. 41, No. 4, 1968, p. 1032, describe that a solution of an alcohol and iodosobenzene in dry dioxane gave the corresponding aldehydes. That DMSO is an oxidizing catalyst for the production of aldehydes is also seen in W. W. Epstein, et al., "Dimethyl Sulfoxide Oxidations," Chemical Reviews, Vol. 67, No. 3, May, 1967, pp. 247-260.
H. P. Kaufmann, et al., in "Die Darstellung hoherer Fettaldehyde," Chemische Berichte, Vol. 91, 1958, pp. 2127-2129 teaches selenium dioxide as a catalyst for the oxidation of alcohols to aldehydes. The oxidation of cyclopropanemethanol to cyclopropanecarbaldehyde using an aqueous solution of 1N in ceric ammonium nitrate is described by L. B. Young, et al. in "Cerium(IV) Oxidation of Organic Compounds. III. Preparation of Cyclopropanecarbaldehyde from Cyclopropanemethanol," J. Org. Chem., Vol. 32, 1967, pp. 2349-2350.
The catalysts used in this invention, the iron phthalocyanines, are known to catalyze the production of detergent range alcohols and ketones from the corresponding alkanes according to U.S. Pat. No. 4,978,799.
While there are a plethora of syntheses for oxidizing primary alcohols to aldehydes, many of the catalysts used have significant disadvantages. For example, using DMSO gives toxic by-products, although DMSO itself is relatively safe. Iodosobenzene, ceric ammonium nitrate, chromium trioxide in pyridine, selenium dioxide and lead tetraacetate are all toxic materials. Iodosobenzene is additionally relatively expensive. There remains a need for a simple synthesis of aldehydes from primary alcohols that has little or no toxicity concerns and which employs relatively inexpensive catalysts.